[PATCH] usbcore PCI glue updates for PM

This updates the PCI glue to address the new and simplified usbcore suspend
semantics, where CONFIG_USB_SUSPEND becomes irrelevant to HCDs because
hcd->hub_suspend() will always be called.

  - Removes now-unneeded recursion support

  - Go back to ignoring faults reported by the wakeup calls; we expect them
    to fail sometimes, and that's just fine.

The PCI HCDs will need simple changes to catch up to this, like being able
to ignore the setting of CONFIG_USB_SUSPEND.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 drivers/usb/core/hcd-pci.c |  106 +++++++++++++++++++++------------------------
 drivers/usb/core/hcd.h     |    6 +-
 2 files changed, 53 insertions(+), 59 deletions(-)

drivers/usb/core/hcd-pci.c

@@ -30,6 +30,8 @@
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <linux/usb.h>
+
+#include "usb.h"
 #include "hcd.h"
 
 
@@ -197,6 +199,26 @@ int usb_hcd_pci_suspend (struct pci_dev *dev, pm_message_t message)
 
 	hcd = pci_get_drvdata(dev);
 
+	/* Root hub suspend should have stopped all downstream traffic,
+	 * and all bus master traffic.  And done so for both the interface
+	 * and the stub usb_device (which we check here).  But maybe it
+	 * didn't; writing sysfs power/state files ignores such rules...
+	 *
+	 * We must ignore the FREEZE vs SUSPEND distinction here, because
+	 * otherwise the swsusp will save (and restore) garbage state.
+	 */
+	if (hcd->self.root_hub->dev.power.power_state.event == PM_EVENT_ON)
+		return -EBUSY;
+
+	if (hcd->driver->suspend) {
+		retval = hcd->driver->suspend(hcd, message);
+		if (retval) {
+			dev_dbg (&dev->dev, "PCI pre-suspend fail, %d\n",
+				retval);
+			goto done;
+		}
+	}
+
 	/* FIXME until the generic PM interfaces change a lot more, this
 	 * can't use PCI D1 and D2 states.  For example, the confusion
 	 * between messages and states will need to vanish, and messages
@@ -215,31 +237,13 @@ int usb_hcd_pci_suspend (struct pci_dev *dev, pm_message_t message)
 	 */
 	has_pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM);
 
-	switch (hcd->state) {
-
-	/* entry if root hub wasn't yet suspended ... from sysfs,
-	 * without autosuspend, or if USB_SUSPEND isn't configured.
+	/* Downstream ports from this root hub should already be quiesced, so
+	 * there will be no DMA activity.  Now we can shut down the upstream
+	 * link (except maybe for PME# resume signaling) and enter some PCI
+	 * low power state, if the hardware allows.
 	 */
-	case HC_STATE_RUNNING:
-		hcd->state = HC_STATE_QUIESCING;
-		retval = hcd->driver->suspend (hcd, message);
-		if (retval) {
-			dev_dbg (hcd->self.controller, 
-					"suspend fail, retval %d\n",
-					retval);
-			break;
-		}
-		hcd->state = HC_STATE_SUSPENDED;
-		/* FALLTHROUGH */
+	if (hcd->state == HC_STATE_SUSPENDED) {
 
-	/* entry with CONFIG_USB_SUSPEND, or hcds that autosuspend: the
-	 * controller and/or root hub will already have been suspended,
-	 * but it won't be ready for a PCI resume call.
-	 *
-	 * FIXME only CONFIG_USB_SUSPEND guarantees hub_suspend() will
-	 * have been called, otherwise root hub timers still run ...
-	 */
-	case HC_STATE_SUSPENDED:
 		/* no DMA or IRQs except when HC is active */
 		if (dev->current_state == PCI_D0) {
 			pci_save_state (dev);
@@ -248,7 +252,7 @@ int usb_hcd_pci_suspend (struct pci_dev *dev, pm_message_t message)
 
 		if (!has_pci_pm) {
 			dev_dbg (hcd->self.controller, "--> PCI D0/legacy\n");
-			break;
+			goto done;
 		}
 
 		/* NOTE:  dev->current_state becomes nonzero only here, and
@@ -259,28 +263,29 @@ int usb_hcd_pci_suspend (struct pci_dev *dev, pm_message_t message)
 		retval = pci_set_power_state (dev, PCI_D3hot);
 		if (retval == 0) {
 			dev_dbg (hcd->self.controller, "--> PCI D3\n");
-			retval = pci_enable_wake (dev, PCI_D3hot, hcd->remote_wakeup);
-			if (retval)
-				break;
-			retval = pci_enable_wake (dev, PCI_D3cold, hcd->remote_wakeup);
-		} else if (retval < 0) {
+
+			/* Ignore these return values.  We rely on pci code to
+			 * reject requests the hardware can't implement, rather
+			 * than coding the same thing.
+			 */
+			(void) pci_enable_wake (dev, PCI_D3hot, hcd->remote_wakeup);
+			(void) pci_enable_wake (dev, PCI_D3cold, hcd->remote_wakeup);
+		} else {
 			dev_dbg (&dev->dev, "PCI D3 suspend fail, %d\n",
 					retval);
 			(void) usb_hcd_pci_resume (dev);
-			break;
 		}
-		break;
-	default:
+
+	} else {
 		dev_dbg (hcd->self.controller, "hcd state %d; not suspended\n",
 			hcd->state);
 		WARN_ON(1);
 		retval = -EINVAL;
-		break;
 	}
 
-	/* update power_state **ONLY** to make sysfs happier */
+done:
 	if (retval == 0)
-		dev->dev.power.power_state = message;
+		dev->dev.power.power_state = PMSG_SUSPEND;
 	return retval;
 }
 EXPORT_SYMBOL (usb_hcd_pci_suspend);
@@ -336,20 +341,9 @@ int usb_hcd_pci_resume (struct pci_dev *dev)
 				dev->current_state);
 		}
 #endif
-		retval = pci_enable_wake (dev, dev->current_state, 0);
-		if (retval) {
-			dev_err(hcd->self.controller,
-				"can't enable_wake to %d, %d!\n",
-				dev->current_state, retval);
-			return retval;
-		}
-		retval = pci_enable_wake (dev, PCI_D3cold, 0);
-		if (retval) {
-			dev_err(hcd->self.controller,
-				"can't enable_wake to %d, %d!\n",
-				PCI_D3cold, retval);
-			return retval;
-		}
+		/* yes, ignore these results too... */
+		(void) pci_enable_wake (dev, dev->current_state, 0);
+		(void) pci_enable_wake (dev, PCI_D3cold, 0);
 	} else {
 		/* Same basic cases: clean (powered/not), dirty */
 		dev_dbg(hcd->self.controller, "PCI legacy resume\n");
@@ -371,17 +365,17 @@ int usb_hcd_pci_resume (struct pci_dev *dev)
 
 	dev->dev.power.power_state = PMSG_ON;
 
-	hcd->state = HC_STATE_RESUMING;
 	hcd->saw_irq = 0;
 
-	retval = hcd->driver->resume (hcd);
-	if (!HC_IS_RUNNING (hcd->state)) {
-		dev_dbg (hcd->self.controller, 
-				"resume fail, retval %d\n", retval);
+	if (hcd->driver->resume) {
+		retval = hcd->driver->resume(hcd);
+		if (retval) {
+			dev_err (hcd->self.controller,
+				"PCI post-resume error %d!\n", retval);
 			usb_hc_died (hcd);
 		}
+	}
 
-	retval = pci_enable_device(dev);
 	return retval;
 }
 EXPORT_SYMBOL (usb_hcd_pci_resume);

drivers/usb/core/hcd.h

@@ -182,12 +182,12 @@ struct hc_driver {
 	int	(*start) (struct usb_hcd *hcd);
 
 	/* NOTE:  these suspend/resume calls relate to the HC as
-	 * a whole, not just the root hub; they're for bus glue.
+	 * a whole, not just the root hub; they're for PCI bus glue.
 	 */
-	/* called after all devices were suspended */
+	/* called after suspending the hub, before entering D3 etc */
 	int	(*suspend) (struct usb_hcd *hcd, pm_message_t message);
 
-	/* called before any devices get resumed */
+	/* called after entering D0 (etc), before resuming the hub */
 	int	(*resume) (struct usb_hcd *hcd);
 
 	/* cleanly make HCD stop writing memory and doing I/O */